/**
* Returns class probabilities for an instance.
*
* @param instance the instance to compute the distribution for
* @return the class probabilities
* @throws Exception if distribution can't be computed successfully
*/
public double[] distributionForInstance(Instance instance) throws Exception {
// replace missing values
m_replaceMissing.input(instance);
instance = m_replaceMissing.output();
// possibly convert nominal attributes
if (m_convertNominal) {
m_nominalToBinary.input(instance);
instance = m_nominalToBinary.output();
}
return m_tree.distributionForInstance(instance);
}
/**
* Classifies the given instance using the linear regression function.
*
* @param instance the test instance
* @return the classification
* @throws Exception if classification can't be done successfully
*/
public double classifyInstance(Instance instance) throws Exception {
// Transform the input instance
Instance transformedInstance = instance;
if (!m_checksTurnedOff) {
m_TransformFilter.input(transformedInstance);
m_TransformFilter.batchFinished();
transformedInstance = m_TransformFilter.output();
m_MissingFilter.input(transformedInstance);
m_MissingFilter.batchFinished();
transformedInstance = m_MissingFilter.output();
}
// Calculate the dependent variable from the regression model
return regressionPrediction(transformedInstance, m_SelectedAttributes, m_Coefficients);
}
/**
* Builds the classifier.
*
* @param data the data to train with
* @throws Exception if classifier can't be built successfully
*/
public void buildClassifier(Instances data) throws Exception {
// can classifier handle the data?
getCapabilities().testWithFail(data);
// remove instances with missing class
Instances filteredData = new Instances(data);
filteredData.deleteWithMissingClass();
// replace missing values
m_replaceMissing = new ReplaceMissingValues();
m_replaceMissing.setInputFormat(filteredData);
filteredData = Filter.useFilter(filteredData, m_replaceMissing);
// possibly convert nominal attributes globally
if (m_convertNominal) {
m_nominalToBinary = new NominalToBinary();
m_nominalToBinary.setInputFormat(filteredData);
filteredData = Filter.useFilter(filteredData, m_nominalToBinary);
}
int minNumInstances = 2;
// create a FT tree root
if (m_modelType == 0)
m_tree =
new FTNode(
m_errorOnProbabilities,
m_numBoostingIterations,
m_minNumInstances,
m_weightTrimBeta,
m_useAIC);
// create a FTLeaves tree root
if (m_modelType == 1) {
m_tree =
new FTLeavesNode(
m_errorOnProbabilities,
m_numBoostingIterations,
m_minNumInstances,
m_weightTrimBeta,
m_useAIC);
}
// create a FTInner tree root
if (m_modelType == 2)
m_tree =
new FTInnerNode(
m_errorOnProbabilities,
m_numBoostingIterations,
m_minNumInstances,
m_weightTrimBeta,
m_useAIC);
// build tree
m_tree.buildClassifier(filteredData);
// prune tree
m_tree.prune();
m_tree.assignIDs(0);
m_tree.cleanup();
}
/**
* Builds a regression model for the given data.
*
* @param data the training data to be used for generating the linear regression function
* @throws Exception if the classifier could not be built successfully
*/
public void buildClassifier(Instances data) throws Exception {
if (!m_checksTurnedOff) {
// can classifier handle the data?
getCapabilities().testWithFail(data);
// remove instances with missing class
data = new Instances(data);
data.deleteWithMissingClass();
}
// Preprocess instances
if (!m_checksTurnedOff) {
m_TransformFilter = new NominalToBinary();
m_TransformFilter.setInputFormat(data);
data = Filter.useFilter(data, m_TransformFilter);
m_MissingFilter = new ReplaceMissingValues();
m_MissingFilter.setInputFormat(data);
data = Filter.useFilter(data, m_MissingFilter);
data.deleteWithMissingClass();
} else {
m_TransformFilter = null;
m_MissingFilter = null;
}
m_ClassIndex = data.classIndex();
m_TransformedData = data;
// Turn all attributes on for a start
m_SelectedAttributes = new boolean[data.numAttributes()];
for (int i = 0; i < data.numAttributes(); i++) {
if (i != m_ClassIndex) {
m_SelectedAttributes[i] = true;
}
}
m_Coefficients = null;
// Compute means and standard deviations
m_Means = new double[data.numAttributes()];
m_StdDevs = new double[data.numAttributes()];
for (int j = 0; j < data.numAttributes(); j++) {
if (j != data.classIndex()) {
m_Means[j] = data.meanOrMode(j);
m_StdDevs[j] = Math.sqrt(data.variance(j));
if (m_StdDevs[j] == 0) {
m_SelectedAttributes[j] = false;
}
}
}
m_ClassStdDev = Math.sqrt(data.variance(m_TransformedData.classIndex()));
m_ClassMean = data.meanOrMode(m_TransformedData.classIndex());
// Perform the regression
findBestModel();
// Save memory
m_TransformedData = new Instances(data, 0);
}
